ES2873023T3 - Head coil arrangement for an MRI device with enhanced immobilization - Google Patents

Abstract

A head coil arrangement (300) for an MRI device (100), comprising - a helmet-shaped coil housing (310) comprising at least one conductor holder (311, 312) extending over a distance up to a head support plane and forms between a receiving space (313) for the head of a patient, and - a head fixation structure (320) that is supported, through at least one leg ( 321), by the conductor holder (311, 312) so that it penetrates at least partially into the reception space (313) and is configured to be brought into contact without harshness with the patient, where the structure (320) for fixing the The head is integrally molded with the coil housing (310).

Description

DESCRIPTION

Head coil arrangement for an MRI device with enhanced immobilization

Field of the invention

The present invention relates generally to magnetic resonance image (MRI) guided radiotherapy. In particular, the present invention relates to a head magnetic resonance (MRI) coil arrangement, a magnetic resonance imaging device and an immobilization method that provides better immobilization of the patient.

Background of the invention

Medical imaging is commonly used to aid in the diagnosis and / or treatment of patients. Magnetic resonance imaging (MRI) is an example of a medical imaging technology commonly performed during the diagnosis and treatment of tumors. To this end, MRI can be performed at the same time as the tumor is diagnosed and irradiated, the radiation being able to be performed, for example, by a linear accelerator system (LINAC).

In order to irradiate the tumor in the best possible way, without compromising the healthy tissue surrounding the tumor, high-quality MR images are sought. To do this, MRI can use local radio frequency coils (RF coils) as a receiver and / or transmitter that, for example, increase the SNR (signal-to-noise ratio) to obtain better quality images. These RF coils can be included in a magnetic resonance coil arrangement. Such a local RF coil can be arranged in the area of a patient's head and can therefore be referred to as a head MRI coil. For example EP 1113287-2 and US 8190237 B2 describe such a head MRI coil.

Furthermore, when using MRI for diagnosis and / or treatment, it is generally desired that the patient move as little as possible. An advantage is that this generally produces higher quality images during imaging as, for example, blurry artifacts within images can be avoided. In this sense, the longer the image acquisition time, the more important it is that the patient move as little as possible. Similarly, during irradiation, for example, during MR-LINAC treatment, the patient should move as little as possible, as any unexpected movement can lead to an unsafe situation. Such an unsafe situation may be inadvertent irradiation of healthy tissue.

Therefore, various position sensing methods have been proposed in the prior art to detect patient movement. For example, document US 6259942 B1 describes a nozzle used as a reference device to be detected by a position sensor. Additionally, document US 2017/0032538 A1 proposes a computer-implemented method to determine a false movement followed by a movement correction system during medical image scanning, where one or more markers are placed on one or more parts of the patient. . Similarly, US 2017/0065830 A1 discloses a head coil arrangement provided with a plurality of fiducial markers that are configured to emit magnetic resonance signals, wherein images of these markers are taken and their position is evaluated and determines the position of the head coil.

Additionally, to avoid or at least reduce the movements of the patient, various fixing means have been proposed. For example, US 8099 150 B2 discloses a head support assembly configured to be removably attached to an MRI scanner gantry or treatment table, wherein a plurality of head support rods are associated with each other. adjustable to the head support frame, they are configured to hold the patient's skull. Additionally, document US 2015/0119902 A1 proposes to arrange a frame around the patient's head and to screw fixation pins connected to the frame to a bone of the skull, which requires a surgical or invasive procedure. Another proposal is directed at a mask in the form of a net that is placed on the patient's head and fixed to a treatment table. These proposals have in common the drawback that fixation can be uncomfortable for the patient due to invasive contact with the skull. Also, the adjustment time required to position and fix the patient's head may be too long. Additionally, by inserting screws into the patient's skull, they can interfere with the radiation beam during treatment.

US 2009/0048508 A1 describes a fixation apparatus for optimizing the fixation position of a stereotactic base ring to the head of a subject. The fixation apparatus comprises one or more fixation elements that allow the fixation apparatus to be releasably fixed to a stereotactic base ring.

V. MENON et al .: "Design and efficacy of a head-coil bite bar for reducing movement-related artifacts during functional MRI scanning" BEHAVIOR RESEARCH METHODS, INSTRUMENTS AND COMPUTERS, vol. 29 no. 4, December 1, 1997, describe the design, construction, application, and efficacy of a single bite bar for use with a full-head MRI coil to reduce artifacts related to the head movement during functional brain imaging. Therefore, it remains a need to provide sufficient fixation and positioning of the patient, during imaging and / or radiation treatment of tumors, that is as comfortable as possible for the patient.

Summary of the invention

One aspect of the present invention provides a head coil arrangement, as defined in independent claim 1, for a magnetic resonance imaging (MRI) device with a helmet-shaped coil housing comprising at least one conductor holder extending over a distance to a plane that supports the head and forms a receiving space for the head of a patient in between. The head coil arrangement further comprises a head attachment structure which is supported by the conductor holder, through at least one leg, such that it at least partially penetrates the receiving space and is configured to make a smooth contact with the patient.

In this context it can be understood that, thanks to the helmet shape of the coil shell, the forehead, face, eyes, nose, cheeks, mouth and / or chin are at least partially surrounded by the shell. coil. Consequently, the reception space may be enclosed. Preferably, the coil housing can be configured as a full face helmet. The head fixation structure can preferably be configured to make non-harsh contact with the patient, which in particular includes non-surgical contact and / or non-invasive contact (i.e., where the tooth is not penetrated or injured). healthy tissue). In particular, there is no coupling with a cranial bone of the patient, for example the skull. Additionally, within the conductor holder a conductor may be arranged which may be formed of a coiled wire.

A number of advantages can be achieved with this configuration of the head coil arrangement. On the one hand, the coil housing, necessary in any case to carry the RF coil, fulfills a double function, namely, it also serves as a support for the head fixing structure. Thus, the movement of the patient's head can be reduced. On the other hand, non-invasive contact with the patient reduces adjustment time and increases patient comfort, especially in patients with a tendency to claustrophobia. Additionally, as the head fixing structure is supported by the coil housing, these two components form a structural unit, which further reduces the adjustment time by being able to arrange and move them together.

In one embodiment of the invention, the frame structure may further comprise at least one first conductor holder and at least one second conductor holder which together span a plane of conductors that at least partially surround the receiving space. In other words, the coil housing can carry several conductors that form a head RF coil carried by the coil housing, wherein the head RF coil can be configured as a multi-channel head RF coil. Furthermore, when arranged in the receiving space, the conductors can span the head of the patient.

Therefore, the head coil arrangement provides both a good signal-to-noise ratio and increased immobilization of the patient.

According to a further embodiment of the invention, the head fixing structure is made of an electromagnetically inert material. The material can be a composite and / or plastic material, such as epoxy resin, polyester, polyacrylamide, vinyl ester resin, wood, ceramic, aramid, fiberglass, polyethylene, etc.

Therefore, MRI is not affected by the head fixation structure arranged between the patient's head and the RF coil and / or the radiation source. In particular, blurry artifacts within images can be avoided.

In accordance with the invention, the head attachment structure is integrally molded with the coil housing. In other words, the head attachment structure and the coil housing can be integrally formed from the same material. Also, the leg arranged between the head fixing structure and the coil housing can be integrally molded with the coil housing and the head fixing structure.

Therefore, the head coil arrangement can be provided as a compact structural unit.

In one embodiment of the invention, the head attachment structure may comprise a bite-lock nozzle. This mouthpiece can be customized for an individual patient. As explained above, the nozzle is an integral part of the coil housing. In addition, it ensures a smooth contact when held in the mouth and if used correctly it does not penetrate or damage the oral mucosa.

Therefore, the patient's head can be fixed simply by grasping the mouthpiece with the mouth. As a result, the eyes and face remain free, which is more comfortable for patients with a tendency to claustrophobia. In particular, the oral cavity of the patient can be immobilized. In addition, a vacuum can be generated by a pump fluidly connected to the mouthpiece to secure the jaw of the patient.

According to a further embodiment of the invention, the head fixation structure may comprise a chin guard. With respect to the chin of a patient, the chin rest may have a concave shape, in particular like a basket, which conforms to the chin from the outside. For example, the chin rest may be arranged to push the chin against a support surface for the head, for example, which may be a stretcher that supports the patient or a part of the coil housing where the head rests, from a opposite direction to the head support surface.

Therefore, due to the smooth surface contact with the chin, the head attachment structure is even less disruptive to the patient and thus provides greater comfort. In particular, most of the patient's face is not in contact with a restriction surface, which is beneficial for claustrophobic patients.

In a further embodiment of the invention, the head fixation structure may comprise a frontal bone abutment. For example, the frontal bone support may be arranged to contact the frontal bone and push it against a supporting surface of the head, for example, which may be a stretcher supporting the patient or a part of the carcass. the coil where the head rests, from a direction opposite the head support surface.

Therefore, due to the smooth surface contact with the frontal bone, the head fixation structure is even less disruptive to the patient and thus provides greater comfort. In particular, most of the patient's face is not in contact with a restriction surface, which is beneficial for claustrophobic patients.

It should be noted that, in another embodiment of the invention, the aforementioned mouthpiece, chin rest and frontal bone rest can be combined within the head fixation structure.

Therefore, the patient's head can be supported by at least three different positions, which simultaneously provides effective restriction of possible movements of the patient's head and provides the patient with the comfort of a less restricted vision.

According to a further embodiment of the invention, both the head attachment structure and the coil housing may comprise at least one fiducial marker arranged so as to be traceable within an MR image. By way of example, the fiducial markers can be infrared (IR) markers or the like. Next, other embodiments of the fiducial marker will be described.

Therefore, any movement of the patient can be detected. In addition, the movement of the head fixing structure relative to the coil housing can be detected. This can significantly increase safety because, for example, the radiation source can be deactivated during unwanted movement.

In a further embodiment of the invention, the coil housing may comprise at least one first sensor configured to measure the signal propagation time to determine the position of the patient relative to the coil housing. The first sensor can be used as said fiducial marker on the side of the coil housing, in this case no external IR light is used. Additionally, the first sensor can be configured as a time-of-flight sensor, for example, a time-of-flight camera system that measures the direct time of flight required for a single pulse of light (for example, a photon) to exit the first sensor and reflected back, for example, into a focal plane array of the first sensor. In other words, for example, the first sensor sends and receives infrared signals, where the time difference between sending and receiving can be multiplied by the speed of light to determine the distance between the patient and the casing of the device. coil. The first sensor may be embedded in the coil housing material due to its small overall size. The first sensor can be used for different tasks during MRI and / or treatment. For example, the first sensor can capture the position or an image of the patient's head and / or face. A data processing device, which can be part of an MR device, can be configured for facial recognition based on the data provided by the first sensor. Additionally, the coil housing can also comprise several, for example two, three, four or more, first sensors, which can be connected to each other and / or to a data processing device to computationally build a multidimensional model of the head. and / or the patient's face. For different measurement tasks, the first sensors may have different characteristics, such as higher resolution and lower speed, lower resolution and higher speed, or the like.

Thus, the first sensor can capture three-dimensional images that can contain complete spatial and temporal data, imaging fully three-dimensional scenes with a single pulse of light. In addition, the patient's eye movement can be captured. Compared with X-ray or MRI images, the construction of a multidimensional model using the first sensor configured as a time-of-flight sensor is not invasive, since, for example, IR light is used. Furthermore, the first sensor provides fast imaging, eg less than milliseconds, high resolution, eg on the sub-mm scale, and is low energy. Additionally, the first sensor is mechanically and electrically robust and available at low cost.

Furthermore, the first sensor can be used for patient adjustment by measuring the distance between the patient's skin and the RF coil. This measured distance can be used as a trigger to send a stop lock signal to a LINAC and / or the MRI scanner.

The first sensor can additionally be used for quality control and / or registration of the head attachment structure, for example the anterior nozzle, prior to MRI and / or treatment. In this regard, the head attachment structure can be optically detected by the first sensor, a 3D model can be created, and can be compared with the reference data assigned to the individual head attachment structure. The reference data may consist of a 3D reference model that is stored in a patient database. Therefore, degradation of performance and / or assignment of the head fixation structure to the wrong patient can be avoided.

Additionally, the first sensor can be used to create a 3D model of the patient's head that can be combined with the 3D model data corresponding to the one or more coils housed within the coil housing, as well as the 3D anatomical data. of the patient's skeleton, for example from a CT scanner during the calculation of the treatment dose. This combined data can be used to determine the Specific Absorption Rate (SAR) in order to achieve an optimal balance between SAR, MRI image quality, and patient head position. This equilibrium can be performed with the finite element method (FEM) and / or an electromagnetic simulator (EM). Therefore, exceeding the predetermined SAR and thus increasing the temperature inside the patient can be avoided.

According to a further embodiment, the coil housing may comprise at least one second sensor configured to measure light absorption or light remission in transillumination of the patient's skin. The first sensor can be used as the previous fiducial marker on the side of the coil housing, no IR light being used in this case. Additionally, the second sensor can be configured as, for example, a photoplethysmography (PPG) sensor that basically illuminates the patient's skin and measures changes in light absorption. Accordingly, the second sensor can provide a non-contact imaging method for collecting live signals from the patient. Additionally, the data from the second sensor can be combined with the data from the first sensor for patient identification purposes, eg for facial recognition, where the second sensor can provide properties of the patient's skin.

Therefore, by using the second sensor, the properties of the skin, heart rate and respiration, mental stress and / or sleep patterns etc. can be measured. of the patient. Based on such information, treatment or shutdown can also be controlled in the event of an emergency or the like.

In another embodiment, the head coil arrangement may further comprise at least one acoustic transducer disposed in the head attachment structure and configured to send an acoustic signal through one or more cranial bones to the inner ear of the patient. The acoustic transducer can be an electromechanical actuator using bone conduction, the sound of which is conducted to the inner ear through the cranial bones and / or bones of the skull.

Therefore, headphones are not needed to provide communication between the physician and the patient, and the patient can wear ear protection, for example, earplugs or the like. As a result, the patient can still hear sound instructions from doctors while requiring less space around the patient's ears. In addition, humans can normally hear sound when the frequency of acoustic signals is between 20 Hz and 20 kHz. Consequently, the preferred operating frequency of the acoustic transducer is between 20 Hz and 20 kHz. Therefore, the operating frequency is significantly below the frequency of the typical MRI signal used in MRI, for example, around 64 MHz for a 1.5 T r M scanner. will generate MRI artifacts. Additionally, the mechanical vibrations generated by the acoustic transducer are small enough not to adversely affect the head attachment structure.

Another aspect of the invention provides a magnetic resonance (MR) device comprising an MR scanner and head coil arrangement in accordance with one or more of the embodiments discussed above. The MRI scanner may comprise a port and a gantry or a stretcher for patient support.

This MRI device improves immobilization of the patient due to the fixation structure for the head of the head coil arrangement.

In one embodiment of the invention, the MRI device may further comprise a data processing device configured to create a multidimensional model of a patient's head based on data provided by one or more sensors arranged in the head coil arrangement. . These sensors can be, for example, the previous time of flight sensor, the previous PPG sensor, etc.

Therefore, the model can be used through a joint clinical workflow. For example, the model can be used to reduce patient adjustment time, as the model provides information that indicates a preferred head location and / or a safe distance within an MRI device.

According to one embodiment of the invention, the model comprises three geometric dimensions enlarged by a fourth time-related dimension.

Thus, the 4D model can be used as a primary imaging guide for radiotherapy, thereby reducing an invasive demand for X-ray and / or MR imaging.

In another embodiment of the invention, the MRI device may further comprise a timing device communicatively connected to both the head coil arrangement and the MRI scanner and configured to temporarily place an electrical component of one of the MRI scanner. magnet and the head coil arrangement in a different operating state, while performing a specific task with each other from between the MRI scanner and the head coil arrangement. The synchronization device can be an electronic device.

In this way, MRI artifacts caused by an electrical and / or electronic device can be avoided, since these can be deactivated, for example, by cutting off the power supply or the like.

According to one embodiment of the invention, the synchronization device may be configured to temporarily change a light emitted by a light source arranged in a hole of the MRI scanner while controlling the measurement through one or more optical sensors arranged in the head coil arrangement.

Therefore, the light inside the hole may change to a color less sensitive to the IR light from the second sensor. For example, the light inside the hole can change to a bluish spectrum that does not affect the optical measurement of the second sensor. This can also be done for only a few milliseconds, with the patient hardly appreciating this change or not appreciating it at all.

In another embodiment of the invention, the timing device is configured to temporarily turn off the power supply to one or more optical sensors arranged in the head coil arrangement during imaging by the MRI scanner.

Therefore, the timing device can temporarily turn off the power to the first and / or second sensors during MRI, for example while an MRI signal receiver and / or an MRI signal readout is active. In this way, the first sensor and / or the second sensor are deactivated and the head coil arrangement is temporarily converted to a conventional head coil without generating MRI artifacts. In accordance with one embodiment of the invention, the timing device is configured to temporarily turn off the power source of the acoustic transducer of the head coil arrangement during imaging by the MRI scanner.

Therefore, the electronic noise of the acoustic transducer can be suppressed. In this way, acoustic communication is only disabled for a short period of time, during which no MRI artifacts are generated.

One aspect of the invention provides a method of immobilization of a head within an MRI device as defined in independent claim 18.

The method can be implemented by the aforementioned head coil arrangement and / or MRI device.

The method comprises:

- providing a helmet-shaped coil housing comprising at least one conductor holder that extends over a distance to a support plane for the head and forms a receiving space for the head of a patient in between,

- providing a head attachment structure, which is supported, through at least one leg, by the conductor holder in such a way that it penetrates at least partially into the receiving space, and is configured to come into non-invasive contact with the patient,

- where the movement with respect to the coil housing and / or the head fixing structure is monitored using one or more markers and / or one or more sensors arranged on the coil housing and / or on the structure fixation of the head.

Thus, the method improves immobilization of a patient's head during imaging and / or MR treatment. In particular, the head fixing structure is supported by the coil housing forming a single structural unit.

According to one embodiment of the invention, the method further comprises:

- scan a surface of the patient's head using one or more sensors,

- creating a multidimensional model of the patient's head based on the data obtained by the scan, and - verifying, based on the model, whether the position of the patient's head is correct.

Therefore, the coil housing and / or the head fixation structure carry technical equipment to monitor the position of the patient's head.

Alternatively or additionally, both the head attachment structure and the coil housing comprise at least one fiducial marker arranged so that it can be tracked within an MRI image, whereby the position of the arrangement can be determined. head MRI coil and further map it with the patient's head surface scan and anatomical data inside the patient's brain.

Therefore, monitoring of the patient's head position can be improved.

In another embodiment of the invention, real-time planning of the treatment dose is performed based on the model.

Therefore, a beam shape can be generated that does not pass through, for example, the coil conductors or any electronics arranged within the receiving space and / or the coil housing of the head coil arrangement. . In this way, such electronics are less affected by radiation and inducing radiation activity can be avoided.

It should be noted that the above-described embodiments can be combined with each other to obtain a synergistic effect that can overcome the independent technical effects of individual characteristics. Also, the above method can be modified by the above embodiments of the head coil arrangement and / or MRI device and vice versa.

Brief description of the figures

Next, exemplary embodiments of the invention will be described with reference to the following figures.

Figure 1 illustrates an MRI device having a support stretcher and a head MRI coil arrangement that is disposed thereon, in accordance with an example outside the scope of the invention.

Figure 2 shows a head MRI coil arrangement according to one embodiment of the invention. Figure 3 illustrates a head MRI coil arrangement in accordance with another embodiment of the invention. Figure 4 shows a head MRI coil arrangement according to another embodiment of the invention. Figure 5 shows a head MRI coil arrangement according to another embodiment of the invention. Figure 6 illustrates a head MRI coil arrangement in accordance with another embodiment of the invention. Figure 7 shows a block diagram of an MRI device according to one embodiment of the invention.

Figure 8 shows a principle of modeling using a time-of-flight sensor arranged in a head MRI coil arrangement in accordance with an embodiment of the invention.

Figure 9 shows a flow chart of a method for installing and / or immobilizing a patient within an MRI device, in accordance with one embodiment of the invention.

The figures are merely schematic representations and only serve to illustrate the invention. Identical or equivalent items are consistently provided with the same reference signs.

Detailed description of realization examples

In the following, a detailed description of exemplary embodiments will be made to explain the invention in more detail.

Figure 1 schematically illustrates an MRI device 100 comprising an MRI scanner 200 with a hole 210, a patient support table 220 positioned on the floor, and a head MRI coil arrangement 300 disposed on the table 220. Inside provided from the hole 210 is a first light source 211 that emits visible light. A second light source 230, which also emits visible light, is disposed outside of hole 210 in a side wall or ceiling.

An upper surface of the stretcher 220 defines a plane LP of rest for a recumbent patient (not shown) and can optionally be moved in and out of the port 210 of the MR scanner 200. The head MRI coil arrangement 300 is positioned on the upper surface of the stretcher 220 and comprises a helmet-shaped coil housing 310 with a plurality of first conductors 311 and a plurality of second Conductor holders 312. The first conductor holders 311 extend parallel to a longitudinal axis of the coil housing 310, the longitudinal axis of which is parallel to that of the stretcher 220. The second conductor holders 312 extend circumferentially about the longitudinal axis. The coil housing 310 is made of an electromagnetically inert material, preferably a suitable plastic and / or composite material. The conductors 311, 312 extend over a distance to the plane LP of rest, which also supports the patient's head, and forms a receiving space 313 for the patient's head in between. Additionally, the conductors 311, 312 each carry an electrical cable (not shown) that together form an RF coil 314 for receiving RF signals, wherein the conductors 311, 312 together span a conductive plane that partially surrounds the receiving space. 313.

The head coil arrangement 300 comprises a head fixation structure 320 for fixing the patient's head within the receiving space 313. By way of example, the head fixation structure 320 is supported, via a leg 321, by the second conductor holder 312. Both the head fixing structure 320 and the leg 321 are made of an electromagnetically inert material, preferably a suitable plastic and / or composite material. In the present exemplary embodiment, the head fixing structure 320 and the leg 321 are formed integrally, that is, in one piece, with the coil housing 310, so the materials are the same. It should be noted that the head fixation structure 320 and leg 321 are adjustable with respect to the patient, ie, the receiving space. Additionally, the head fixation structure 320 penetrates the receiving space 313 and is configured for non-invasive contact with the patient. Various positions for non-invasive patient contact and respective embodiments, as well as examples outside the scope of the present invention of the head fixation structure 320 will be described below. In accordance with these examples, the head attachment structure 320 comprises a bite-lock mouthpiece 322 that is removably attached to the leg 321 so that it is interchangeable and the coil housing 310 can be reused with another patient. .

Figure 2 shows one embodiment of the head coil arrangement 300 as a single component. It comprises at least two fiducial markers 330 that are visible and / or traceable within the MR images. At least one of the fiducial markers 330 is disposed on the coil housing 310 and at least one other is disposed on the head attachment frame 320. The head coil arrangement 300 further comprises a plurality of first sensors 340, which in this embodiment are designed as time-of-flight sensors, e.g. ex. as on-chip sensors. Each of the first sensors 340 is configured to measure a signal propagation time between the first sensor 340 and the patient, for example, to determine the position of the patient relative to the coil housing 310 and / or to adjust the MRI device 100, as well as the patient, etc., as described below. The first sensors 340 are embedded within the material of the coil housing 310, distributed around the receiving space 313 and aligned therewith. Additionally, the head coil arrangement 300 comprises at least one second sensor 350, which in this embodiment is designed as a photoplethysmogram (PPG) sensor, configured to measure light absorption or light remission in skin transillumination. of the patient. Accordingly, the second sensor 350 is configured to measure and / or control heart rate, cardiac cycle, respiration, hypo and hyperkalemia, etc. of the patient. In addition, the second sensor 350 is embedded within the material of the coil housing 310 and aligned toward the receiving space 313. To allow communication between a physician and the patient, the head coil arrangement 300 comprises an acoustic transducer 360 disposed on the head fixation structure 320 and configured to convert electrical signals or, as preferred herein, optical signals into mechanical vibrations and send a sound to the inner ear through the cranial bones of the patient. It should be noted that the first sensors 340, the second sensor 350, and the acoustic transducer 360 are connected to a power source and, at least partially, communicatively connected to a data processing device 110, as described below. Merely as an example, the head attachment structure 320 of these embodiments comprises the bite lock nozzle 322 which can be replaced by other attachment means.

A further embodiment of the head coil arrangement 300 is shown in Figure 3. In principle, it is the same as the one described above. However, in this embodiment, the head attachment structure 320 has another attachment means, namely, a chin guard 323. The chin guard 323 is also attached to the leg 321 and is cup-shaped, thus being configured to at least partially enclose the chin of the patient. In addition, the chin guard 323 is configured to move toward the chin of the patient relative to the coil housing 310.

Figure 4 shows a further embodiment of the head coil arrangement 300, which differs from the previous embodiments primarily in the design of the attachment means. Accordingly, the head attachment structure 320 of this embodiment comprises a frontal bone abutment 324 that is configured to contact the frontal bone of the patient. The frontal bone support is shaped like a bar and conforms to the shape of the frontal bone. In addition, the frontal bone support 324 is configured to move toward the chin of the patient relative to the coil housing 310.

A further embodiment of the head coil arrangement 300 is shown in Figure 5. This embodiment differs from the previous one in that a second leg 321 extends from the coil housing 310. By way of example, the first and second legs 321 are arranged symmetrically with respect to the fixing structure 320 of the head, which may be configured as mouthpiece 322, chin guard 323, or frontal bone rest 324.

Figure 6 shows a further embodiment of the head coil arrangement 300. It differs from the previous embodiments mainly in the design of the conductors 311, 312, that is, in their number, shape and direction of extension. This embodiment has in common with the previous one that the head fixing structure 320 is supported, through the leg 321, by the coil housing 310.

Furthermore, the head attachment structure 320 is designed as explained above. It should be noted that the coil housing 310 can be configured in two parts, with a lower part and an upper part optionally attachable and removable. In this embodiment, the head attachment structure 320 is attached to the top of the coil housing 310.

With reference to Figure 7, which shows a block diagram, the electrical and / or electronic structure of the MRI device 100 will be described. Consequently, the MR device 100 comprises the aforementioned central data processing device 110, which is configured to process the data of the MR device 100 and control its main functions, for example, by means of a processor, an I / O interface. S, etc. The processing device 110 is connected to an MRI post-processing unit 120, a gradient amplifier 130, configured to provide output voltages and currents and to control gradient coils (not shown), a light control unit 140 and a LINAC interface 150. These components have in common that they are arranged in a separate room from the MRI scanner 200 (see also Figure 1), which is indicated in Figure 7 by a frame surrounding the additional components assigned to the scanner 200 of RM or the room that houses them. Within that room, the MRI device 100 further comprises a plurality of optical converters 160, each of which is configured to convert electrical signals that are used outside the room that the MRI scanner 200 accommodates, into optical signals that they are used inside that room. A first optical converter 160 is connected to the MRI post-processing unit 120 located outside the room, and is connected inside the room to an MRI signal reading unit 170, which is also connected to a receiver 180 of signals from the MRI. MRI and RF coil 314. A second optical converter 160 is connected to the LINAC interface 150, located outside the room, and inside the room it is connected to the first and second sensors 340, 350, these sensors 340, 350 being also connected to a storage unit 115, configured as, for example, a flash drive to store data from sensors 340, 350 and / or data processing device 110. A third optical converter 160 is connected to the gradient amplifier 130 and the light control unit 140, located outside the room, and inside the room it is connected to a synchronization device 190. It should be noted that this synchronization device 190 is also connected to the second of the optical converters 160 connected to the LINAC interface 150, the sensors 340, 350, the MRI signal reading unit 170, the MRI signal receiver 180 and the acoustic transducer 360.

Still referring to Figure 7, the functions of the above components will now be described, as well as an operating example of the MRI device 100.

First, the head fixation structure 320 can be used to immobilize the patient's head within the MRI device 100 during MRI and / or treatment. To this end, the patient lies on the stretcher 220 with the head positioned within the receiving space 313 of the head coil arrangement 300 and surrounded by the RF coil 314. The patient's head is then fixed using the head fixation structure 320, wherein at least one of the bite lock mouthpiece 322, chin rest 323, and frontal bone rest 324 is brought into contact. non-invasive with the patient's mouth, chin, or frontal bone to immobilize the head relative to coil housing 310 and RF coil 314.

The first sensor 340 can then be used for various tasks before and / or during MRI and / or treatment. Accordingly, after installation of the patient within the head coil arrangement 300, the first sensor 340 serves to capture the face and / or the contour of the patient's head. In addition, the second sensor 350 captures a property of the patient's skin. The data from the first sensor 340 and the second sensor 350 are then combined and processed, for example, by means of the data processing device 110, for patient identification. To this end, data processing device 110 comprises a software module configured to derive facial recognition from image recognition. Additionally, the first sensor 340 serves to detect and / or register the head attachment structure 320, and in particular the mouthpiece 322 that is customized for the patient. In this regard, one or more of the first sensors 340 scans in 3D, for example, the nozzle 322 and, for example, the data processing device 110 analyzes the data from the first sensor 340 by comparing it with a previously scanned 3D model obtained from a database of patients. As a result, it is verified whether the mouthpiece 322 assigned to the patient is correct and whether it is still usable in qualitative terms. Additionally, through the use of the first sensor 340, the distance between the patient's skin and the RF coil 314 is measured. The measured distance is recorded in the storage unit 115 as a distance threshold. In case the distance between the RF coil 314 and the patient's skin is outside a predefined range and may cause an unexpected increase in radiation dose due, for example, to ERE (electron return effect), the The first sensor 340 can send a radiation beam stop interlock signal to the LINAC interface 150 through the respective optical converter 160. Due to the distance threshold already stored in the storage unit 115, the post-processing unit 120 does not have to form or process MR images to determine the distance between the patient's skin and the RF coil. Compared to measuring distance using MRI, this approach requires less time and is more reliable to avoid unexpected increases in radiation dose. In addition, the first sensors 340 provide a real-time distance measurement that is used in an online radiation dose planning module (not shown). Additionally, one or more of the first sensors 340 can be used to create a 4D model comprising the 3D surface of the patient's head and a 1D timeline. This 4D model is assigned to MRI and / or CT scans and is used throughout the clinical workflow. Accordingly, the 4D model can be used as the primary imaging guide for radiotherapy in order to significantly reduce the demand for X-ray and / or MRI images.

For a better understanding, Figure 8 schematically shows the general use of the first sensor 340. As explained above, one or more first sensors 340 are arranged in the coil housing 310 facing the receiving space 313. The sensor 340 it captures the surface of the patient's head and this data is processed by the data processing device 110 and / or recorded in the storage unit 115.

Referring back to Figure 7, the second sensor 350, in addition to said patient identification, can also be used to detect the heart rate, mental stress, sleep patterns or the like of the patient. This can be done during the training, preparation and treatment of the patient using LINAC. Compared to X-rays, the principle of operation of the second sensor 340 is non-invasive.

In addition, the synchronization device 190 can perform various tasks within the MR device 100. Consequently, since the second sensor 350 is configured as a PPG sensor, the timing device 190 controls the first light source 211 and / or the second light source 230 through the light control unit 140 to change the emitted light. to a spectrum that has, for example, fewer red components, such as blue light. In this way, the emitted light is changed only during the few milliseconds required by the second sensor 350 to measure. In this short period of time, the patient's eye hardly perceives the color change, or does not perceive it at all. Additionally, when the gradient amplifier is active during MRI, the timing device 190 is used to temporarily deactivate, over a range, for example, 100 to 200 milliseconds, one or more of the electronics in the coil array 300. head, such as the first and second sensors 340, 350, the acoustic transducer 360, etc. In this way, these electronic components do not generate electronic noise that can introduce artifacts into MR images. For the same reason, the timing device 190 temporarily disables the acoustic transducer 360.

The fiducial markers 330, which are also disposed within the receiving space 313, allow the position of the head coil arrangement 300, the patient's head, and the head fixation structure 320 to be monitored in real time. By combining the 3D superficial scanning of the patient's head by the first sensor and the internal anatomical data of the patient's brain by the MRI scanner, the positions and dimensions of the patient's head and inner brain can be determined. Therefore, the effects of ERE can be predicted and taken into account during treatment dose planning. In addition, during treatment, the radiation beam can be tailored in real time so that the beam does not pass through the lead wires of the RF coil 314 or other electronic components of the head coil arrangement 300. In this way, electronic components are less affected by radiation.

With reference to Figure 9, which shows a flow chart, an example procedure for immobilization of a head within the MRI device 100 will now be described. As noted above, the method can be modified according to the design and / or operation of the MRI device 100.

First, in a step S1, the helmet-shaped coil housing 310 is provided comprising at least one conductor holder 311, 312 which extends over a distance to a head bearing plane and forms the space between reception 313 for the head of a patient. Then, in a step S2, the head fixing structure 320 is provided which is supported, through at least one leg 321, by the conductor holder 311, 312 so as to at least partially penetrate into the receiving space 313 and it is configured to be placed in non-invasive contact with the patient. Then, in a step S3, the movement of the patient's head relative to the coil housing 310 and / or the head fixation structure 320 is monitored using one or more markers 330 and / or one or more sensors 340. , 350 disposed in the coil housing 310 and / or the head attachment structure 320.

Reference signs

100 MRI device

110 data processing device

115 storage unit

120 MRI Post Processing Unit

130 gradient amplifier

140 light control unit

150 LINAC interface

160 optical converter

170 MRI signal reading unit

180 MRI signal receiver

190 sync device

200 MRI scanner

210 hole

211 first light source

220 stretcher

230 second light source

300 head coil arrangement

310 helmet-shaped coil housing

311 first conductor carrier

312 second conductor holder

313 reception area

314 RF coil

320 head fixing structure

321 leg

322 bite lock nozzle

323 chin guard

324 frontal bone support

330 fiducial marker

340 first sensor (for example, time of flight sensor) 350 second sensor (for example, photoplethysmogram sensor) 360 acoustic transducer

S1-S3 steps of the method.

Claims (20)

A head coil arrangement (300) for an MRI device (100), comprising - a helmet-shaped coil housing (310) comprising at least one conductor holder (311, 312) which extends over a distance to a head support plane and forms between a receiving space (313) for the head of a patient, and - a head fixing structure (320) that is supported, through at least one leg (321), by the conductor holder (311, 312) so that it penetrates at least partially into the receiving space (313) and it is configured to be brought into contact without harshness with the patient, wherein the head attachment structure (320) is integrally molded with the coil housing (310). The head coil arrangement (300) according to claim 1, further comprising at least one first conductor holder (311) and at least one second conductor holder (312) that together span a conductive plane that at least partially surrounds the reception space (313). The head coil arrangement (300) according to claim 1 or claim 2, wherein the head attachment structure (320) is made of an electromagnetically inert material. The head coil arrangement (300) according to any one of the preceding claims, wherein the head attachment structure (320) comprises a bite lock nozzle (322). The head coil arrangement (300) according to any one of the preceding claims, wherein the head attachment structure comprises a chin guard (323). The head coil arrangement (300) according to any one of the preceding claims, wherein the head attachment structure comprises a frontal bone support (324). The head coil arrangement (300) according to any one of the preceding claims, wherein both the head attachment structure (320) and the coil housing (310) comprise at least one fiducial marker ( 330) arranged so as to be traceable within a magnetic resonance image. The head coil arrangement (300) according to any one of the preceding claims, wherein the coil housing (310) comprises at least one first sensor (340) configured to measure a signal propagation time to determining the position of the patient relative to the coil housing (310). The head coil arrangement (300) according to any one of the preceding claims, wherein the coil housing (310) comprises at least one second sensor (350) configured to measure light absorption or remission light on the transillumination of the patient's skin. The head coil arrangement (300) according to any one of the preceding claims, further comprising at least one acoustic transducer (360) disposed on the head attachment structure (320) and configured to send a signal acoustic to the inner ear of the patient through one or more of the bones of the skull. 11. A magnetic resonance imaging device (100), comprising - an MRI scanner (200), and - a head coil arrangement (300) according to any one of the preceding claims. The MRI device (100) according to claim 11, further comprising a data processing device (110) configured to create a multidimensional model of a patient's head based on data provided by one or more sensors (340, 350) arranged in the head coil arrangement (300). The magnetic resonance device (100) according to claim 12, wherein the pattern comprises three geometric dimensions enlarged by a fourth time-related dimension. The magnetic resonance device (100) according to claim 12 or 13, further comprising a synchronization device (120) communicatively connected to both the head coil arrangement (300) and the resonance scanner (200) and configured to temporarily place a component (211, 340, 350, 360) of one of the MRI scanner (200) and the head coil arrangement (300) into a different operating state during a specific task performed with the other from between the magnetic resonance scanner (200) and the head coil arrangement (300). The magnetic resonance device (100) according to claim 14, wherein the synchronization device (120) is configured to temporarily change the light emitted by a light source (211) arranged in a hole (210) of the scanner (200) while monitoring a measurement via one or more optical sensors (340, 350) arranged in the head coil arrangement (300). The magnetic resonance device (100) according to claim 14 or 15, wherein the synchronization device (120) is configured to temporarily deactivate the power supply of one or more optical sensors (340, 350) arranged in the head coil arrangement (300) during imaging by the MRI scanner (200). The magnetic resonance device (100) according to any one of claims 14 to 16, wherein the synchronization device (120) is configured to temporarily disable the power source of an acoustic transducer (360) of the arrangement (300) of head coil during imaging by the MRI scanner (200). 18. A method of immobilizing a head within an MRI device (100), comprising: - providing (S1) a helmet-shaped coil housing (310) comprising at least one conductor holder (311, 312) that extends over a distance to a head support plane and forms a receiving space ( 313) for the head of a patient, and - providing (S2) a head fixing structure (320), which is supported, through at least one leg (321), by the conductor holder (311, 312) so as to penetrate at least partially into the space of reception (313) and is configured for smooth contact with the patient, wherein the head attachment structure (320) is integrally molded with the coil housing (310), - where the relative movement with respect to the casing (310) of the coil and / or the structure (320) for fixing the head is monitored (S3) using one or more markers (330) and / or one or more sensors (340, 350) arranged in the coil housing (310) and / or the head fixing structure (320). 19. The method according to claim 18, further comprising: - scan a surface of the patient's head using one or more sensors (340, 350), - creating a multidimensional model of the patient's head based on the data obtained by the scan, and - verifying (S5), based on the model, whether the position of the patient's head is correct. The method according to claim 19, wherein, based on the model, real-time treatment dose planning is performed.